This invention relates to a vapor cooling device for cooling a heat generation member, and more particularly to improvements in a cooling member abutting against a heat generation member.
Heretofore it has been difficult to provide small-sized cooling members for use with vapor cooling systems. For example, in order to make a vapor cooled semiconductor device small-sized, the cooling member therefore must be decreased in dimension. This decrease in size is accompanied by an increase in thermal flux flowing through the heat transfer surface of the small-sized cooling member to a refrigerant contacting that surface. At a moderate thermal flux or less, the refrigerant boils in a region of nuclear ebullition in which bubbles in the form of string-like beads are successively generated from the heat transfer surface of the cooling member; but at extremely high thermal fluxes, the boiling state of the refrigerant is such that a film of vapor from the refrigerant covers the entire heat transfer surface and bubbles of the refrigerant are intermittently generated and raised from the film of vapor. In the latter case the refrigerant is called as boiling in a region of film ebullition. This may result in the thermal destruction of the device due to an abrupt rise in temperature. To avoid this difficulty requires much labor and skillful manufacturing technique.
Accordingly it is an object of the present invention to provide a new and improved cooling member simple in configuration and simply manufactured to permit the resulting device to be low in thermal resistance and also to be small-sized.